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Topic Review (Newest First)

01-23-2013 06:06 PM

71nova355

VR1 10-30 good zinc oil at your local parts store!

ive had great luck with Valvoline VR1 racing synthetic and eveyone else ive talked to that uses this oil also has never had a problem. Good zinc oils are out there but there pricey. additives are good too. just dont skimp. Plus you broke in the motor without a tach and if you tell comp that they wont help you.

Its a bummer things happened the way they did but take it as a learning experience and make the necessary changes for this next time. 383 in an awd s10? sounds like a lot of fun! Changing to a roller set up isnt a bad idea but very good motors are built everyday with flat tappet cams. The cams these days are incredible and you should have no problem hitting the rpm your motor is built for with a flat tappet cam, solid or hydroulic.

I hope things work out for you and im sure many others will be glad to help you through this. This site is filled with knowledge worth paying for!

01-23-2013 05:51 PM

cdminter59

Flattened Comp cam, am I SOL?

While we are on the subject of camshaft failure, you think it is another way to make more money? Comp has the Pro Plasma Nitriding Process maybe this is what they would like to sell everyone buying a hydraulic flat tappet camshaft. I read that the addition of nitriding may require a cam core upgrade so this would be more money! It is something to think about.

01-23-2013 10:47 AM

oldbogie

Quote:

Originally Posted by Studebaker

Before you say anything, I know this post is a months old. I have had numerous failures with Compcams camshafts in the last 10 years, I no longer use them. They always have some excuse not to warranty anything. I have had real good luck with Isky and Howards brand cams. I do not believe the ZDDP excuse. If this was true, small four stoke engine camshafts (Briggs& Stratton, Honda, Yamaha, Etc) would also be having record number of failures, but this is not the case. Yes, there is the arguement that these small engines do not have high valve spring pressures but neither do most mild SBC and BBC rebuilds. You be the judge, I know what my verdict is, I will never use Compcams products again.

The Root Cause of the problem with modern fast lift flat tappet cams is just that; "fast lift". This works really well for making power by getting rid of the extremely long ramps used so often on the engines of muscle cars back in the day and are still popularly made and sold by Howards, Engle, Isky and even Comp and Lunati among others. We get into what Harvey Crane calls "Hydraulic Intensity"; that being the amount of lift per degree of duration expressed as a ratio. The more aggressive the lift per degree the more important ZDDP becomes as such lobes require a lot of spring pressure to keep the lifter tracking the lobe shape. This causes the interface between the lobe and lifter to squeegee the oil from their interface. But the attractive advantage of the fast lift rate (actually the fast settle rate in closing the intake) is the reduction in the loss of mixture mass from the reversion forces of the rising piston (the essence of DCR calculation). This builds much stouter bottom end torque reducing the need for low ratio gearing and it keeps the power peaks from jumping into considerably higher RPM bands than the older slower rate cams, while retaining all the power a long duration gives at the top RPMs. But the big downside is wear, this is actually a two sided coin where spring pressure is concerned where the recommended high pressure springs wipe lube from the lobe/lifter interface right at a point in history where ZDDP is being greatly reduced (ZDDP provides a constantly renewing dry lubricant into the interface that is not easily squeegeed by the forces in that interface); the flip side is where a lot of people get into trouble not using the comparable kit for these high rate cams which then lets the lifter bounce on the lobe when the valve is suddenly closed. The lack of spring pressure may even allow the valve to loft going over the top of the lobe then slamming the lifter back into the lobe after said lobe passes out from under the lifter. These are not Briggs and Stratton kinds of problems. The OEM addressed this issue back in the mid 1980s with a near universal change to roller cams, only trucks with very mild cam timing and lift soldiered on with flat tappet cams for a few more years all of these gone to rollers by 1996.

Best advice I can offer is use a retro roller kit in anything but a stock truck engine rebuild. Second best advice is if you just gotta have one of these fast ramp flat tappet cams along with it, put in the thrust snubber button used for old fashion roller cams in these early blocks, these at least relieve the lobe/lifter interface (and the distributor gear) of having to keep a preload on the timing gear to block thrust faces. A little less for the lobe and lifter to do and it positively reduces and lateral excursions of the cam to .005 inch or a bit less so there isn't any (much) side to side rubbing of the lifter face against the lobe allowing it to spin in its bore without being dragged or pushed side to side at the same time.

Bogie

01-22-2013 09:16 PM

Studebaker

Compcams failures

Before you say anything, I know this post is a months old. I have had numerous failures with Compcams camshafts in the last 10 years, I no longer use them. They always have some excuse not to warranty anything. I have had real good luck with Isky and Howards brand cams. I do not believe the ZDDP excuse. If this was true, small four stoke engine camshafts (Briggs& Stratton, Honda, Yamaha, Etc) would also be having record number of failures, but this is not the case. Yes, there is the arguement that these small engines do not have high valve spring pressures but neither do most mild SBC and BBC rebuilds. You be the judge, I know what my verdict is, I will never use Compcams products again.

05-14-2012 07:17 PM

Mojo56

NEVER EVER use any oil rated SM with any flat tappet cam... the detergent additives in the oil will remove the built up phosphorus on the engine parts and will kill the cam.

05-10-2012 05:54 AM

CNC BLOCKS NE

Another big problem is cam companies sometimes are not using good cam cores. On alll my HYD and solid lifter cams I have always used the P-55 cam core. Its a harder cam core then the standard cam cores!!

05-09-2012 06:10 PM

big_c_snow

Well, not only did it ruin all my bearings, turns out my crank is not saveable. So, I'm out the cost of a new one of those, plus balancing. Crap.

At least I managed to find a fresh stock 350 for $300. Gonna go ahead and stick that in my truck while I debate whether or not I am suited to building complete performance engines.

Oh, and it occurred to me after the fact to plug the bypass. Next time, if there is one.

Thanks for the info on the oil though, I'll make sure to get a roller cam engine next time.

And Comp offered me a discount on a new cam and lifters, which I probably won't be taking.

Hello folks, I return with more information on my fresh 383 that had low idle oil pressure. Turns out, in addition to the trash ruining all the bearings and requiring the crank to be turned, the cam is also flat on two lobes. It's a Comp XE268H, and I have slightly stronger than stock valvesprings (not sure what the pressure is though, any way to find out other than a scale that I don't have?)
!

Plugging the oil fitler bypass and running a good filter would have saved your crank from being turned and debis going through your engine.

S-3 15/40 CENPECO oil has 1582 PPM of zinc.

There 20/50 has 2300 PPM of zinc.

05-09-2012 08:00 AM

ap72

If I was comp id say you're sol but offer you a discount on a new cam. Its more than likely not their fault and racing is a hobby where the consumer assumes the risk. Offering a discount would be good customer service though.

05-09-2012 07:45 AM

John long

As a side note here. Uncle Sam mandated that over the road diesel trucks run catalytic converters a few years ago. Hence, all the diesel oils thought to be high in ZDDP are not anymore. I believe this a very serious issue and think that even people who have flat tappet cams that are broken in need to seriously consider a quality ZDDP additive.

John L

05-09-2012 05:06 AM

454C10

another example of a xtreme cam going flat. Voodoos are the same.

Just use an old school 260H or 268H (high energy compcam) and it will live a long happy life. Maybe not make as much power as the XE at first, but XE's don't make much power with a few flat lobes and chewed up engine bearings.

This is the reason I always recommend starting out with a complete 96 to 2000 350 vortec engine with factory roller cam and vortec heads.

Make sure to check the lifter bore clearance. I had a BBC that ate cams and it was from extra tight lifter bores. Roller lifters require even more clearance than a regular flat tappet lifter. 0.001 to 0.0015" for a flat tappet and 0.0015 to a 0.002" for a roller lifter.

05-09-2012 05:02 AM

CNC BLOCKS NE

Quote:

Originally Posted by big_c_snow

Hello folks, I return with more information on my fresh 383 that had low idle oil pressure. Turns out, in addition to the trash ruining all the bearings and requiring the crank to be turned, the cam is also flat on two lobes. It's a Comp XE268H, and I have slightly stronger than stock valvesprings (not sure what the pressure is though, any way to find out other than a scale that I don't have?)

Problem is, I bought it through my college about four years ago, but only just got it into a vehicle and running. I followed all the directions explicitly, assembly lube, Comp lifters, correct oil (Rotella T 15W-40) with GM EOS, 2000+ rpm (no tach) for twenty or so minutes.

Think I have a case for a warranty claim through them? I ask before I waste my time and money calling them and sending the cam off for them to verify it is indeed flat.